Articles on Medical Diseases and Conditions

Entries Tagged ‘Medical Parasitology’


Microsporidia are intracellular-living spore-forming protozoa, classified into more than 50 genera and over 600 species. They infect various animals and nonvertebrates. Some nonvertebrate hosts are mosquitos, honey bees, fish, and grasshoppers. In humans, clinical disease has only recently been noticed, and only in persons with AIDS. Here, the predominant species is Enterocytozoon bieneusi, which primarily […]

Strongyloides Stercoralis

Strongyloides is a small roundworm that infects the small intestine. Many cases are asymptomatic, but some infections produce diarrhea. In immunocompromised persons, especially those with AIDS, infection may spread to organs or tissues outside the intestine and become fatal. About 70%-80% of infected persons are said to have eosinophilia, but immunocompromised persons with systemic larval […]

Trichomonas Vaginalis

This motile flagellated protozoan infests the vagina and labial area in the female and the prostate and urethra of the male. Estrogen effect on vaginal epithelial cells is a predisposing factor toward infestation in females, so that trichomoniasis is uncommon before puberty or after menopause. The infection is usually transmitted during sexual intercourse, although some […]

Trichinella Spiralis

The larvae of this small roundworm are usually ingested with raw or insufficiently cooked pork or insufficiently cooked meat products contaminated by infected pork. During the first week after ingestion, symptoms consist of nausea and diarrhea; these may be minimal or absent. About 7-8 days after ingestion there is onset of severe muscle pain, which […]


The fish tapeworm Diphyllobothrium latum (Dibothriocephalus latus) is only rarely a problem in the United States. The organisms are ingested with raw pike fish from the Great Lakes area. Usually very few symptoms are produced, but occasionally the syndrome of megaloblastic anemia may result from ingestion of dietary vitamin B12 by the parasite. Diagnosis consists […]


Hookworm is a problem in some areas of the southern United States and occasionally may be the cause of an iron-deficiency anemia in children. Routine stool examination for ova and parasites is usually adequate for diagnosis.

Pinworm (Enterobius Vermicularis or Oxyuris Vermicularis)

Infestation with pinworms is fairly common in children. The female worm lays her eggs at night around the anal region. The best diagnostic procedure, therefore, is some method to swab the anal region thoroughly with an adhesive substance such as transparent celluloid tape (Scotch tape). The sticky surface with the eggs can then be directly […]

Schistosoma Mansoni

Schistosoma mansoni is sometimes encountered in the United States because it is endemic in Puerto Rico. Routine stools for parasite ova are often not sufficient, because the adult lays its eggs in the venous system, and the ova must penetrate the intestinal mucosa to appear in the stool. In difficult cases, proctoscopic rectal biopsy with […]


Leishmaniasis is caused by a protozoan of the genus Leishmania that includes many species, some of which cause more than one clinical syndrome. Leishmaniasis is best known in the Middle East but also occurs in the Far East (except Japan), various areas of Africa, Central and South America, and occasionally in the European side of […]


Cryptosporidium is another sporozoan organism with some similarities to Toxoplasma. It was originally found in cattle with diarrhea, where it caused diarrhea in calves (predominantly 7-14 days old but sometimes up to 30 days old). Other animals and some birds (including turkeys and chickens) also can become infected. Cryptosporidium was next reported to cause diarrhea […]